click on the o2 sensor link in the first post ron.

u could measure at the ECU,between D14(white/red) & ground(black wire on A plug),just flip the little flap open on the back of the plugs,it will give u better access to the pins to measure,becareful not to short anything out with your probes.

it should fluctuate on idle between about 0.1 & 1V,if it just stays low then it is lazy or possibly your "magic" rom is just idling lean.If i was u i would promptly bury that rom & appoint the new engine manager & then work from there.

btw do u still have your old dead sensor,i might be interested in it?